1. Field of the Invention
The present invention relates to an alarm device for a vehicle, an alarming method for a vehicle, and an alarm generation program. In particular, the present invention relates to an alarm device for a vehicle, an alarming method for a vehicle, and an alarm generation program for a vehicle, for generating alarms relating to objects such as a “red light”, a “stop sign” and a “pedestrian” existing ahead of the own vehicle at appropriate timings while learning driving characteristics of the driver.
2. Related Art
Inventions have been proposed to enable the timing of generating an alarm to be adjusted while considering driving characteristics of a driver, in an alarm device for a vehicle to alert the driver of the own vehicle that an object such as a “red light”, a “stop sign” or a “pedestrian” urging a stop to the own vehicle exists.
Japanese Patent Application Laid-open No. 2002-220035 (paragraph [0020] and FIG. 1) (Patent Document 1) describes an alarm device for a vehicle, in which a driver sets a characteristic value relating to the driving characteristics of the driver with a dial, and the value is assigned to an equation which has been stored on the device so as to calculate an inter-vehicular distance for generating an alarm (hereinafter referred to as an inter-vehicular distance for an alarm), and when the distance from the own vehicle to the object becomes smaller than the inter-vehicular distance for an alarm, an alarm is generated. According to this invention, timing of an alarm is adjustable by setting a dial value freely.
Japanese Patent Application Laid-open No. 2003-141697 (paragraphs [0065] to [0069]) (Patent Document 2) describes an alarm device for a vehicle in which an inter-vehicular distance for an alarm is calculated from a free running time computed from the current point to a point before a predetermined time (a time period from a point where a driver feels braking is required to a point he/she actually presses the brake pedal) and the own vehicle average deceleration speed, and when the distance from the own vehicle to the object becomes smaller than the inter-vehicular distance for an alarm, an alarm is generated. According to this invention, two parameters, that is, (1) free running time and (2) own vehicle average deceleration speed, are set while considering the driving record up to the point before the predetermined time and the secondary statistic, so it is possible to set alarm timing for each driver while reflecting the driving characteristics of the driver.
Further, as an alarming technique for only a case of approaching a precedent vehicle, there is known a device which alerts a driver to an approach to a precedent vehicle during traveling at an appropriate timing. Japanese Patent Application Laid-open No. 8-132931 (pp. 3-4, paragraph [0045] and FIG. 4) (Patent Document 3) describes a travel control device for a vehicle in which based on an inter-vehicular distance, the own vehicle speed and a relative speed with the precedent vehicle during traveling while following the precedent vehicle, an inter-vehicular distance for starting deceleration is calculated from a predetermined driver model so as to follow the precedent vehicle under conditions of constant deceleration speed or deceleration time, and based on the inter-vehicular distance for starting deceleration, travel of the own vehicle is controlled and an alarm is generated.
Japanese Patent Application Laid-open No. 7-159525 (paragraph [0013] and FIG. 6) (Patent Document 4) describes a precedent vehicle approaching alarm device in which a value of (inter-vehicle distance/relative speed) of a deceleration starting time is learned, and based on the value, a timing of generating an alarm to alert each driver to an approach of the precedent vehicle is controlled.
However, there was a problem that the accuracy of timing to be calculated had a limitation in the conventional art since the deceleration speed of the own vehicle was assumed to be constant, which was common in the conventional art. Since the deceleration speed is not constant in an actual deceleration operation, there is required a system capable of describing the driving characteristics of a driver in detail.
Further, relating to the invention of Patent Documents 2 to 4, there is a problem when extracting values of average deceleration rate, free running time, and (inter-vehicular distance/relative speed) at the time of starting deceleration from the actual travel history of a driver. In order to extract the average deceleration rate and (inter-vehicle distance/relative speed) at the time of starting deceleration, it is required to further specify a deceleration starting operation accurately. However, since the decelerating operation is performed in various events, it is not easy to specify an intended decelerating manipulation among many decelerating operations. Similarly, as for a free running time, it is required to specify the time when a driver is aware of a necessity of deceleration. However, it is very difficult to specify such a time. Further, until drive history data of a certain number of times or hours is obtained in order to calculate a primary or secondary static of moving characteristics from the past drive history, it must depend on an initial value or the like.